ADD: added @marshmellow42 's changes to "lfdemod"

diff --git a/client/cmdhftopaz.c b/client/cmdhftopaz.c
index a982b88a9ff8dc7b3a006049ee40902daf44bd94..2f9bc3dc0102ddf1bbbe4c199726eb3d3ccc7d04 100644 (file)
--- a/client/cmdhftopaz.c
+++ b/client/cmdhftopaz.c
@@ -258,7 +258,7 @@ int CmdHFTopazReader(const char *Cmd) {
        uint8_t rid_response[8];
        uint8_t *uid_echo = &rid_response[2];
        uint8_t rall_response[130];
-       bool verbose = true;
+       bool verbose = TRUE;
 
        char ctmp = param_getchar(Cmd, 0);
        if ( ctmp == 'S' || ctmp == 's') verbose = FALSE;

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 862d05ba5addd355f744c908a10f13b1857685b0..cb3e9f0b8a417aa9198262b38d0df42000a1bddd 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -261,9 +261,9 @@ void askAmp(uint8_t *BitStream, size_t size)
 {
        for(size_t i = 1; i<size; i++){
                if (BitStream[i]-BitStream[i-1]>=30) //large jump up
-                       BitStream[i]=127;
+                       BitStream[i]=255;
                else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
-                       BitStream[i]=-127;
+                       BitStream[i]=0;
        }
        return;
 }
@@ -463,10 +463,10 @@ int gProxII_Demod(uint8_t BitStream[], size_t *size)
                //return start position
                return (int) startIdx;
        }
-       return -5;
+       return -5; //spacer bits not found - not a valid gproxII
 }
 
-//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
+//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
 {
        size_t last_transition = 0;
@@ -490,6 +490,7 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
        // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
        // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
        // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
+       //  (could also be fc/5 && fc/7 for fsk1 = 4-9)
        for(idx = 161; idx < size-20; idx++) {
                // threshold current value
 
@@ -497,23 +498,24 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
                else dest[idx] = 1;
 
                // Check for 0->1 transition
-               if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
+               if (dest[idx-1] < dest[idx]) {
                        preLastSample = LastSample;
                        LastSample = currSample;
                        currSample = idx-last_transition;
                        if (currSample < (fclow-2)){            //0-5 = garbage noise (or 0-3)
                                //do nothing with extra garbage
-                       } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves  or 3-6 = 5
+                       } else if (currSample < (fchigh-1)) {           //6-8 = 8 sample waves  (or 3-6 = 5)
+                               //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
                                if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample     == 0 )){
-                                       dest[numBits-1]=1;  //correct previous 9 wave surrounded by 8 waves
+                                       dest[numBits-1]=1;
                                }
                                dest[numBits++]=1;
 
-                       } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = garbage 
+                       } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = unusable garbage 
                                //do nothing with beginning garbage
-                       } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's
+                       } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
                                dest[numBits++]=1;
-                       } else {                                         //9+ = 10 sample waves
+                       } else {                                        //9+ = 10 sample waves (or 6+ = 7)
                                dest[numBits++]=0;
                        }
                        last_transition = idx;
@@ -523,6 +525,7 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 }
 
 //translate 11111100000 to 10
+//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
                uint8_t invert, uint8_t fchigh, uint8_t fclow)
 {
@@ -534,6 +537,7 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
                n++;
                if (dest[idx]==lastval) continue; 
                
+               //find out how many bits (n) we collected
                //if lastval was 1, we have a 1->0 crossing
                if (dest[idx-1]==1) {
                        n = (n * fclow + rfLen/2) / rfLen;
@@ -542,6 +546,7 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
                }
                if (n == 0) n = 1;
 
+               //add to our destination the bits we collected          
                memset(dest+numBits, dest[idx-1]^invert , n);
                numBits += n;
                n=0;
@@ -696,7 +701,6 @@ int PrescoDemod(uint8_t *dest, size_t *size) {
        return (int) startIdx;
 }
 
-
 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
 // BitStream must contain previously askrawdemod and biphasedemoded data
 int FDXBdemodBI(uint8_t *dest, size_t *size)
@@ -1495,8 +1499,8 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
        numBits += (firstFullWave / *clock);
        //set start of wave as clock align
        lastClkBit = firstFullWave;
-       //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);  
-       //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
+       if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);  
+       if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
        waveStart = 0;
        dest[numBits++] = curPhase; //set first read bit
        for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
@@ -1679,7 +1683,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
        i=0;
        // warning - overwriting buffer given with raw wave data with ST removed...
        while ( dataloc < bufsize-(clk/2) ) {
-               //compensate for long high at end of ST not being high... (we cut out the high part)
+               //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
                if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
                        for(i=0; i < clk/2-tol; ++i) {
                                buffer[dataloc+i] = high+5;
@@ -1694,7 +1698,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
                        }
                }
                newloc += i;
-               //skip next ST
+               //skip next ST  -  we just assume it will be there from now on...
                dataloc += clk*4;
        }
        *size = newloc;